Regulator circuits regulate (reduce) an external supply voltage to an internal voltage used for internal circuits such as memory and logic circuits. Regulator circuits are applied to various semiconductor integrated circuit devices.
For example, a regulator circuit is available which reduces an external supply voltage (Vin), supplies a low power internal voltage (Vos) to an internal circuit in a standby state (Sw), and supplies a high power internal voltage (Vo) to the internal circuit in an active state (Sa).
However, such a regulator circuit causes, for example, noise (coupling noise) when shifting from a standby state to an active state, leading to difficulty in supplying a stable internal voltage to an internal circuit.
As a solution for reducing the influence of coupling noise, for example, a capacity for holding a reference voltage (Vr) may be increased or the supply current of a reference voltage generating circuit for generating the reference voltage may be increased. In addition, the reference voltage generating circuit may be switched between a standby state and an active state.
Unfortunately, this technique is not preferable because a current consumed in a standby state is increased or the circuit area is expanded or becomes complicated.
Incidentally, in the past, various suggestions have been presented as regulator circuits which reduce an external supply voltage, convert the level to an internal voltage suitable for an internal circuit, and output it.
Patent Document 1: Japanese Laid-open Patent Publication No. 2006-146421
Patent Document 2: Japanese Laid-open Patent Publication No. 2014-128038